A nice little revision exercise to check that children are confident with counting across the hundreds boundary and also have quick mental arithmetic strategies.

These questions are all subtracting a single digit from a multiple of 100. Some children will do them by counting back, others will employ different strategies such as subtracting 10 and adjusting. Generally, we are looking for quick and accurate methods.

The last three questions ask children to write down the method they usedm, which can reveal a lot.